Now, they're opening up a bit about what life was like on-set when the cameras were off.
From their relationships with their co-stars to casting secrets, Savage, who played Kevin Arnold, and McKellar, who portrayed his love interest, Winnie Cooper, told ABC News all about their time on the show, which aired from 1988 to 1993. (Can't get enough? Season one is available on DVD now, complete with more behind-the-scenes anecdotes.)
1. Winnie Cooper Wasn't Always a Series Regular: When McKellar was auditioning for the part of Winnie Cooper, she was only allowed to do so because the character was simply a guest role and her family didn't allow her to try out for main parts. Then, things changed. "My mom said, 'Listen, they're offering for this to be a series regular. We have to think about this. This could really change your life and acting is supposed to just be a hobby,'" McKellar recalled. "I begged, like, 'This is so much fun. I really want to do it!' and she's like, 'OK, but I'm putting a loophole in the contract, we're getting a really good lawyer, and if you ever want to get out you can.'"
2. The Stars' Mothers Were a 'United Front': McKellar and Savage credit their parents, along with co-star Josh Saviano's mother Jane, for keeping them in line and out of trouble. "They were strong moms who cared about their kids more than fame," McKellar said. "That's actually not that common in Hollywood." Savage agreed: "All our parents had that in common -- that they thought our well-being and our education was more important than anything. They kind of became this united front, safeguarding us," he said. "We all really benefited from the strengths of our families and friends for sure."
3. For the McKellars, 'The Wonder Years' Was a Family Affair: Not did Danica McKellar play sweet girl-next-door Winnie Cooper, but her sister Crystal played recurring character Becky Slater, who had a crush on, and simultaneously bullied Kevin Arnold. "Crystal and I both auditioned for the part of Winnie Cooper and it came down to the two of us," she said. "They ended up hiring me, but they said they loved Crystal and they meant it. They said, 'We're gonna write a part if this goes to series,' and they wrote a part for her." In the end, their respective roles were representative of who they actually were in real-life. "I remember in fifth grade, there were these boys who were teasing me, and Crystal went and kicked them in the shins for me!" McKellar said. "She's a lawyer now." Savage laughed. "She's channeling that aggression in a more healthy way now!" he joked.
5. And Jason Hervey Acted as a Surrogate Older Brother: For Savage, Jason Hervey, who played his big brother Wayne on-screen, was "exactly a big brother to me." While Savage said that Hervey would pick on him from time to time, they shared a lot of good times too. "When he got a license, he got a sports car and he drove me all around town," he said. "He had all these cool cars and all these great girls and all these cool friends and he would every once in a while give me a glimpse into his life and let me tangentially experience it. He was everything you'd want in a big brother." (Meanwhile, McKellar said she also felt like she had brothers on the set, and credited Savage with teaching her the meaning of the phrase, "Pull my finger.")
7. Fred Savage's First Kiss Was with Danica McKellar: Like McKellar, Savage said he had his first kiss on the show. "Growing up, there were a lot of firsts [on-set]," he explained. "But that's true of that time in your life. Every day is some first!"